1. Field of the Invention
This invention relates to circuit breakers with auxiliary switches which provide an indication of the state of the circuit breaker contacts, and in particular to small circuit breakers for residential and light industrial and commercial use incorporating such an auxiliary switch.
2. Background Information
Large multi-pole circuit breakers typically have a cross bar which links the poles together and opens the contacts in all phases if any phase trips open. Often, an auxiliary switch is provided in such breakers to generate an external indication that the contacts are open such as for electrical interlocks between multiple circuit breakers or for remote monitorina of circuit breaker operation. Since the crossbar provides an indication of the state of the circuit breaker contacts, either opened or closed, the cross bar has been used to actuate the auxiliary switch.
In some circuit breakers an additional switch, called an alarm switch, is included which is actuated when the circuit breaker is tripped, again for remote monitoring of breaker operation.
The small circuit breakers used for residential and light commercial or industrial use have to date not been provided with an auxiliary switch. Adding an auxiliary switch to such small circuit breakers is made difficult by the fact that such breakers typically do not have a cross bar, and is further complicated by the limited space in such breakers which are configured to be mounted in a standardized load center or panel board. An instance is known of such a small breaker which is equipped with an alarm switch to provide a remote indication that the circuit breaker is tripped. The switch is mounted in a compartment adjacent the compartment containing the circuit breaker mechanism and has an extension on its plunger which extends through the housing wall and is engaged by the latchable cradle of the circuit breaker mechanism. Unlatching of the cradle to trip the breaker results in actuation of the alarm switch.
There remains a need for a small residential or light industrial or commercial circuit breaker which is provided with an auxiliary switch to generate an electrical indication that the circuit breaker contacts are open. This must be accomplished within a standardized size of such circuit breakers so that they may be continued to be used in the standard load centers and panel boards.